Automatic opening and closing tongs



Feb. 24, 1953 J. T. STONE AUTOMATIC OPENING AND'-CLOSING TONGS 2 SHEETS-SHEET 1 Filed Feb. 4. 1949 FIG 4 I5 glnfimtur .JOHN 7. STONE.

Feb. 24, 1953 J. T.' STONE 2,629,627

AUTOMATIC OPENING AND CLOSING TONGS Filed Feb. 4, 1949 2 SHEETS-SHEET 2 AA 6/ 3 2 a? E 27 Ill JOHN 7 STONE.

Patented Feb. 24, 195

were? UNITED STATES PATENT (OFFICE 2,629,627 mavens P N AN! i e nei Nes z John r. Stone, Baltimore, Md. I Application February 4, 1 949, s"e1 ial i$io..7,4,6t7

2 Claims. (01.

This invention relates to lifting equipment and more particularly to those of the lazy tong variety and employed for gripping, lifting and depositing heavy material and doing so automatically.

While tongs have been used in the steel and heavy metal industries for lifting and carrying ingots and other items or materials, such have in general, requirements .that need the use of additional operators or extra cables for manipulating; their mechanisms .and controlling their positioning. These requirements add to the cost of their operation, while at the same time limiting the amount of work they can accomplish within a certain period of time. Some of the previous devices used powerful magnets and tripping or latching coils which for the most part introduced another element of danger and increase in maintenance expense. The lack of reasonably effective automatic response in the operation of the device and safety in its usehas raised objections of the more serious nature to the previous types of tongs.

In this invention the functional structure is designed to be automatic in action, simple in mechanism and requiring no operators other than one, for controlling theuse of the tongs in a conventional manner. Further no other cable but that-required for lifting the. deviceis needed in its use.

It is an object of this invention to providea new and improved lifting tongs that will avoid one or more of the objections and limitations of the prior art.

Another object of the present invention is to provide a new and improved lifting tongs that will operate automatically to pick up or release a load.

An additional object of the invention is to provide a new and improved lifting tongs that will avoid the use ofallextraneous cables, rods or parts other than the lifting cable, for actuating its mechanism.

An additional object of the present invention is to provied a lifting tong which will open and close automatically when the tongs are dropped against the ground or other object.

Other objects will become apparent as the invention is more fully set forth.

For a better understanding of the invention and the objects thereof, reference is made to the appended drawings. These drawings in conjunction with the following description, outline a particular form of the invention by way of example, not of limitation, in order that the principles thereof may be appreciated and its method of preferred operation fully understood.

In the drawings:

Figure 1 is aside elevationof a pair of automatic opening'and closing tongs, embodying this invention, in open position;

Figure12 is .a plan view of Figure 1;

Figure 3 is a side elevation similar to Figure 1 except, it shows the tongs in closed position;

Figure 4 isanenlarged sectional view showing the latch mechanism;

Figure 5'is'fa side elevation of a modified form of thetong's, shown in open position;

Figure 6 is a side elevation of end view of Figure v5; and

Figure '7 isfan enlarged sectional view showing the latch mechanism.

Similar reference characters pertain to the same parts throughout the drawings.

The particular construction indicated in the drawings, illustratesfl a lazy tongs structure desig'n,ed for lifting, carrying and depositing ingots uppelilportionjwithfa' ring' l2 mounted on the cap] fj'aridusablefor'thejattaohment of a lifting cable [3. The interior E4 of the tubing is also rectangularin section, so that the wall sur- 30 t5 whichlis'. preferably of rectangular form to 'slidablyjf t" in frame iii and reciprocate. longituldinally 'thereinf Thejframe l0 is made of suf- Qficient si'z'atol'enable it to supportthe entire load fplaced 'ontne't ngs during its use. The plunger 15 cannot rotate" about its axis inthe tubing faces thereofncanserve' as guides for a plunger it, an'dthisisa necessary requirement. A slot ,tliis' formed in the, front wall. of the yoke l6 nearthecap flliand runs longitudinally for a suitable .dis'tlance'to'j s'uitthe latch I I rotatably mounted on 'thefplunger liinside the interior f4. Opposite the slot as in the back Wall or the yoke Ill is another slot Id of similar form but slightly longer. The upper edges of slots 56 and [8 are aligned with each other. The latch ll also registers in these slots during its rotation in a manner to be more fully described. The lower portion of the plunger i5 is enlarged into a bifurcated yoke 19 having openings near its free ends to support a shaft 2|. This shaft 2! is the pivot on which the large pincing jaws 23 open and close. They are of conventional arcuate form with their end claws 2t arranged to grasp an ingot preferably adapted for sharpening and hardening. The jaws extend into arms 25 projecting outwardly and drilled adjacent their extremities to provide holes through which pins 22 pass to attach them to the toggle links 21.

The arms 25 are formed at their contacting surfaces to slide cooperatively on one another as the jaws open and close. The toggle links 21 are bifurcated to enable them to straddle the ends of the arms 25 and suitable openings are provided to receive pins 22 so that the arms 25 and links 2? can rotate about the pins 22. The upper end portions 30 of the toggle links 21 have holes therein aligned with holes in the bifurcated end portions or lobes 33. of a saddle 34. These holes receive pins 32 so that the links 21 may swivel about said pins. The saddle 34 is longitudinally slidable on the outer walls of the frame It. The travel of the saddle 34 is limited in its downward direction by lugs 35 mounted on the sides of the yoke Ill. The travel upwardly is restricted by the length of the arms 25 and toggle links 27 when extended as far vertically as they can go.

The latch mechanism consists of a latch I1 pivoted on a pin 35 which extends internally and transversely of the plunger I at its upper portion 34. A through slot 29, alignable with the slots I6 and I8 of the frame It), is provided at this point so that the latch Il may, at times, extend through all of the said slots while pivoting about its pin 36. The latch has its end portions cut into V-like pawls 3Iof unequal length for the purpose of engaging the edge 38 of the slot I6 to immobilize the plunger i5 within the frame It. When this occurs the jaws 23 are wide open, the saddle 34 is resting on the lugs 35 and the cable I3, which is connected to a lifting boom, is taut. When tension in the cable is lessened, the tong mechanism, which rests on the floor, moves downwardly, causes the plunger I5 to move upwardly inside of the frame It and uncovers the point 55 of a deflecting pin 46 rigidly secured to the cap II. This deflector strikes the latch IT at a point to the side of the pivot pin 36 and rotates the latch partially to the left in Figure 4. The point of contact would be, in Figure 4, on the upper face of the latch and to the left of pin 36. The net result of. this action is to remove the lower right hand of the latch from its rest on the edge 38 of the frame I0. When the cable It is pulled upwardly with the jaws still resting on the floor, the frame II] rides upwardly on the plunger I5 and, eventually, the lower edge of the latch to the right of Figure 4, strikes the edge 38 of the frame Ill and pivots about its pin 36. The size of the left hand opening I8 allows the left side of the latch to rotate unhampered and as the cable I3 continues its ascent, the latch moves completely, and in vertical position, within the frame It. During this movement, the jaws 23 have closed about the article to be lifted and moved. When the article has arrived at its destination, the cable I3 is slackened, the toggle mechanism releases its article and the plunger moves upwardly within the frame to a point where the deflector 40 hits the upper end of the latch in its upper V-groove, At this time the jaws are opened to their widest extent and the plunger is at the end of its travel. The longer side of the V-groove, when contacted by the defletcor 4U, partially rotates the latch to the left with its lower V-groove projecting through the slot I5 of the frame II]. The cable I3 is then tensioned and the frame is raised upwards of the plunger I5 until the larger face of the lower V-groove strikes the edge 38 of the frame, as shown in Figure 4. In this position, the frame and the plunger are locked together so long as the cable I3 remains tensioned. The device may then be moved about with the jaws in open position. To release the parts, it is only necessary to slacken the cable by resting the jaws on the floor as explained above and repeat the operation.

While the form illustrating the invention is of preferable types, it is not desired to limit the scope of the invention to such form in particular, since it is appreciated the construction could be varied considerably and be within the scope of the claims.

Having thus described the invention, what is claimed is:

l. Tong mechanism comprising a hollow frame. an abutment carried outwardly by said frame near the lower end thereof, a pair of toggle arms, said arms terminating in jaws at their lower ends, connecting means between the upper ends of said arms straddling the frame above the abutment and normally resting on said abutment, a plunger slidably mounted in said frame, pivot means between one end of said plunger and the lower ends of the toggle arms, releasable locking means between the frame and plunger carried by said plunger, said releasable locking means consists of a latch pivoted to the plunger,

and a deflector for said latch carried by the frame.

2. Tong mechanism as set forth in claim 1 wherein the locking means consist of a latch pivoted to the plunger, said latch having locking surfaces adapted to cooperate with surfaces of the frame, and a deflector carried by the frame to rotate the latch.

JOHN T. STONE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 768,253 Watson Aug. 23, 1904 1,056,343 Kromann Mar, 18, 1913 

